Fix windows serial debugging: the key was other_config:hvm_serial, not platform:hvm_serial
Fix windows serial debugging: the key was other_config:hvm_serial, not platform:hvm_serial

Although platform:hvm_serial makes more sense than other_config.

Signed-off-by: David Scott <63c9eb0ea83039690fefa11afe17873ba8278a56@eu.citrix.com>

johnelse/xcp-rrdd,sharady/xcp-networkd,djs55/squeezed,simonjbeaumont/xcp-rrdd,simonjbeaumont/xcp-rrdd,koushikcgit/xcp-networkd,djs55/xcp-rrdd,koushikcgit/xcp-rrdd,djs55/xcp-networkd,robhoes/squeezed,djs55/xcp-networkd,koushikcgit/xcp-networkd,sharady/xcp-networkd,johnelse/xcp-rrdd,koushikcgit/xcp-rrdd,koushikcgit/xcp-rrdd,djs55/xcp-rrdd